The exibition showcases commissioned photographs documenting preparations for the London 2012 Olympic and Paralympic Games, and runs from July 19 – September 23. Her Royal Highness was welcomed by director of the National Portrait Gallery, Sandy Nairne, who first greeted her back on February 8th, when the Duchess made her initial trip.

Catherine chose a blue Stella McCartney dress for the occasion, pairing it with her black Prada heels. McCartney designed Team GB’s uniforms (J-E-A-L-O-U-S), so this was a brilliant nod on Catherine’s part.

TheCartier necklace (worth almost $77,000) around Catherine’s neck is made of white, yellow and white gold, according to Grazia, who contacted the jeweler for a comment.

It turns out that the Duchess didn’t borrow the necklace and they had no clue she’d be wearing it today. ’Tis part of her private jewelry collection, we assume.

Lookie here! Catherine was featured in the exhibition along with the athletes. A photo of her playing hockey with Team GB at Olympic Park on March 15th was displayed, taken by Jillian Edelstein, according to the Daily Mail‘s Rebecca English.

“She is very, very good, and it shows. She takes beautiful, detailed photographs,” photographer Allistair Morrison has said of Catherine’s work, who curated a show featuring his pictures back in 2007.

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No reputable media outlet is reporting that the Duchess actually paid for this necklace (or that her father-in-law did). If she didn’t borrow it from Cartier, it might have been a gift, like the diamond and ruby set she wore with a black evening dress shortly before last Christmas.